This isn't really a bug with machop, but the bug happened while trying to do this with machop, it happens with any pokemon.
Basically when you go to your PC drag and pull a pokemon to a message the pokemon just kinda sticks there, you'll know when it happens xD
Hopes this helps the developers of Pokemon Revolution Online :Heart:
Edit:
Players please do not do this glitch, the pokemon 'sticker' will be there forever, i will try reinstalling PRO and see if it fixes.